Possibly the most dramatic view in the Solar System, the sixth planet sports rings that can be viewed with a small telescope. It is also the least dense of the planets – less dense than water. Due to its rapid rotation and lower gravity, Saturn is a flattened sphere that bulges in the middle.
The rings of Saturn are very thin. This picture from the Cassini probe shows the shadows of the rings while edge-on the rings are almost invisible. The rings average only 20 m in thickness. This image also shows a storm that has gone completely around the planet. The large gap in Saturn's rings is called the Cassini division. There are many separate rings. Recently, a new moon was discovered forming from the ring material.
When Galileo first observed the rings of Saturn, he called them “ears”. Due to the tilt of Saturn, sometimes the rings are edge-on to Earth and cannot be seen.
Saturn has at least 150 moons. Titan is the largest moon and one we can see from Henize. Titan is larger than Mercury and has an atmosphere that is mostly nitrogen with a little methane. Lakes of liquid hydrocarbons have been found on the surface of Titan. The Huygens lander reached Titan in 2005.
The moon Enceladus has liquid water beneath an ice crust. Geysers of water have been observed to shoot into space. Material in these geysers show organic compounds that suggests life exists in a large ocean below the surface.
Like Jupiter, Saturn has metallic hydrogen in its interior. The lower gravity does not compress it as much, however. The interior of Saturn is hot – 11,700° C – and Saturn radiates 2.5 times the heat it receives from the Sun.
|Semi-major axis||1.43 x 109 km
|Orbital Period||29.46 years|
|Sidereal rotation||10.57 h|
|Mean radius||58,232 km
|Mass||5.68 x 1026 kg
|Mean density||0.687 g/cm3|
|Surface gravity||10.44 m/s2